Tunnel furnace



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TUNNEL FURNACE Filed Sept. 21, 1937 3 Sheets-Sheet 2 17, 1939. P. SCHELOUMOW TUNNEL FURNACE Filed Sept. 21, 19:57 :5 Sheets-Sheet 3 ya .17 g

a fi//// jeloaman 050 Patented Oct. 17, 1939 UNITED STATES PATENT OFFICE TUNNEL FURNACE Peter Scheloumow, Tallinn, Esthonia, assignor to Eesti Patendi Aktsiaselts, Tallinn, Esthonia 4 Claims.

This invention relates to ,a tunnel furnace for distillation, coking and drying purposes, provided with a main heating system which from one end supplies a heating duct extending alongside the 5 distillation tunnel and a heating gas circulating system.

The invention has for its purpose to provide a tunnel furnace or kiln which is suitable for the distillation of bituminous substances of different properties and compositions and, according to the invention, reheaters and separate, individually regulable heating devices for oil or gas are arranged in the heating duct. For or with such a mode of construction, the flow of heat in the longitudinal direction of the distillation furnace can be influenced at any points as regards its quantity and temperature, according to the operative state of the furnace in each case, or in accordance with the requirements in each case of the material to be distilled, whereby the output and economy of the furnace are increased.

Kilns are already known in which several heating points are arranged along the burning chamber. These heating points, however, together produce the requisite distillation temperature and, owing to the absence of a main heating point, there might with a different adjustment of the individual burners no longer be a sufiicient burning temperature. For the rest, with such an arrangement of the burners the burning temperature is only reached in the zone of the last burners, so that a portion of the tunnel cannot be utilised for the burning operation proper.

It has also already been proposed in the case of vertical low temperature carbonisation furnaces and distillation furnaces to provide, besides the main heating system extending alongside the cells or retorts, special heating points for one or more sections of the furnace. These branch heating systems which are intended in the first instance to keep the temperature uniform are, however, branched off directly from the main heating system, so that they are dependent on it and therefore do not ensure such a farreaching independence in the heat regulation as is the case with the arrangement according to the invention. Apart from that, the branch heating systems react on the condition of the main heating system, so that the maintenance of uniform working conditions is made more difiicult.

For carrying the invention into effect the following guiding principles have been found to be most suitable:

In a heating duct for a. tunnel furnace the heat absorbing or transmitting devices or substances must be so arranged that between each two or after a series of them a space is left free, which is of sufiicient size for enabling an additional heating means in the form of an oil or gas burner of smaller power to be operated in it.

The heating oil or gas feeding this additional burner and the requisite air must show a difference in pressure with respect to the interior of the heating duct, which is sufficiently great for producing a rapidly travelling and far extending flame. This flame will play into the heating duct suitably in a known manner at an obtuse angle or in counterflow to the total flow of the heating gas in the heating duct, the result of this being that these flames are bent over and are spread in a fan-shaped manner over the cross-section of the heating duct.

In the accompanying drawings two constructional examples of the invention are illustrated, in which Figure 1 shows in longitudinal sectional elevation a heating duct for a tunnel furnace or oven with the additional heating means,

Figure 2 is a sectional plan taken on line 2-2 of Figure 1,

Figure 3 is a cross-section of same taken on line 3-3 of Figure 1 showing a tunnel furnace with the heating duct adjoining,

Fig. 4 is a cross-section similar to Fig. 3 taken on line 4-4 of Fig. 1,

Fig. 5 shows in longitudinal sectional elevation a heating duct for a tunnel furnace with a modified arrangement of additional heating means,

Fig. 6 is a sectional plan view of Fig. 5, and

Fig. 7 is a cross-section of same taken on line 'l 1 of Fig. 5.

In the drawings the same reference numerals refer to similar parts in the modified construc tions.

Referring to Figures 1 to 3, and 4, ll represents a furnace tunnel adapted for distilling coking 40 and drying purposes, and is preferably of the kind which is divided longitudinally into compartments comprising drying chamber, lock chamber, distilling chamber, a second look chamber and a cooling chamber. [2 is a heating duct arranged alongside the tunnel furnace ll supplied with hot gases from one end thereof, l3 being the return gas fiue. At intervals in the heating duct are reheaters I4 through which hot gases heated in the reheaters circulate by passages 14 to and from the tunnel furnace II. The heating duct I2 is supplied with hot gases at one end by a furnace 24 from whence they pass through the reheaters and return by the return gas flue l3 which passes underneath the heating duct I2. Directly below the floor of the heating duct and arranged between the reheaters are provided combustion chambers l6 into which an air supply pipe I! and a gas or oil pipe l8 enter which are branched from main supplies l9 and 20 passing along the outside wall of the duct.

At the crown of the chamber l6 are openings 2! arranged at an obtuse angle as shown in Figure 1 so that the flames generated at the burners 25 pass into the heating duct in counterfiow direction to that of the main flow of the hot gases, with the result that the flames spread in a fanshaped manner over the cross-section of the heating duct l2.

A similar construction of tunnel furnace and heating duct to that above described is seen in Figures to 7. In this more simple arrangement for supplying the additional or auxiliary heating means, pipes l1 and i8 which are branched from the mains I9 and 20 enter the heating duct I2 through the side Walls thereof, the flame nozzles 25 being set so that the flames are directed counterwise to that of the main flow of the hot gases along the duct l2;

The branch supply pipes l1 and [8 are provided with valves l1 and I8, respectively, for

individually regulating the supply of air and gas.

I claim:

1. A tunnel furnace for distillation coking and drying purposes in combination with a main heating duct extending alongside said tunnel and capable of being swept through from one end with main heating means, reheaters arranged at intervals in the heating duct for transferring heat from said duct to the tunnel furnace, auxiliary heating means arranged at predetermined intervals in said duct for delivering heated gases into the path of travel of the main heating means so as to be deflected by the latter, and means for individually regulating the said auxiliary heating means, for selectively controlling the temperature in the reheaters.

2. A tunnel furnace as claimed in claim 1 in which the auxiliary heating means comprise combustion chambers with fuel burners, supply mains connected therewith, and oblique openings between the chambers and the heating duct for oppositely directing the additional hot gases into said heating duct, whereby said gases will be dis tributed in the main heating means.

3. A tunnel furnace as claimed in claim 1 in which the auxiliary heating means comprise branch pipes connected with air and gas supply mains, nozzles connected to said branches which pass through the side walls to and enter the heating duct by oblique openings so that the flames produced by the additional hot gases are oppositely directed to path of travel of the main heating. means and are distributed in the latter.

i. A tunnel furnace as claimed in claim 1 in which the auxiliary heating means comprise combustion chambers situated below the floor of the heating duct and fuel burners with nozzles within said chambers, in combination with fuel burners the nozzles of which project through the side walls of the heating duct, both of said additional heating means providing for directing the additional hot gases in the opposite direction to the flow of the main heating so as to be distributed throughout the cross sectional area of said heating duct.

PETER SCHELOUMOW.- 

